Analysis of processing technology of box parts

This article focuses on the analysis of the processing technology of box parts from the three aspects of process route preparation, positioning reference selection and main surface processing, and the proposed hole finishing process plan and points out: the processing of important hole systems of box parts Precision becomes the key to the processing technology of box parts. [Keywords] process route formulation; positioning reference selection; box body plane processing; internal stress; hole system processing. Box body parts are typical parts of mechanical parts, such as lathe headboxes, gear transmission boxes, gearbox bodies, etc. , Is one of the basic parts of the machine. It keeps the shafts, bearings, sleeves, gears and other parts of the machine and its components in the correct mutual position, and makes them move in coordination with each other according to the pre-designed transmission relationship, and combine them into one overall. The assembled box parts are installed on the machine with the design reference plane of the box, so the processing quality of the box not only affects its assembly accuracy and movement accuracy, but also has a decisive impact on the machine's working accuracy, performance and life. 1. The design of the process route The box body requires a lot of surface to be processed, such as the head box body of the lathe, the gear transmission box body, etc. Among these processed surfaces, the plane processing accuracy is easier than the hole processing accuracy, so the spindle hole in the box body (mainly The processing accuracy of the hole) and the processing accuracy of the hole system have become the key issue of the process. Therefore, I am more inclined to pay attention to a few points in the arrangement of the process route. (1) The processing sequence of surface first, hole first, the plane is processed first, which not only removes the unevenness of the surface of the blank and the surface sand and other depressions, but more importantly, when processing the holes distributed on the plane, it is convenient to scribe and align. , And when the boring tool starts to boring, it will not produce impact vibration and damage the tool due to the uneven end surface. Therefore, the plane should generally be processed first. (2) Separate the roughing and finishing stages. The box structure is complicated, and the accuracy of the main surface is high. The cutting force, clamping force and cutting heat generated during roughing have a greater impact on the processing accuracy. If roughing is performed immediately Machining, the internal stress of the workpiece deformation caused by various reasons after rough machining is not fully released, and it cannot be eliminated in the finishing process, which will cause the box body to deform when unloading after processing, which affects the final accuracy of the box body. It is believed that in the rough machining process, the fixture should be loosened many times to release the internal stress as much as possible in time and maximize the processing quality of the box. (3) The decision of process concentration or dispersion is in line with the principle of process dispersion for the coarse and finishing stages of the box body. However, in medium and small batch production, in order to reduce the number of machine tools and fixtures used, and to reduce the number of box handling and installation , The roughing and finishing stages can be relatively concentrated, and they can be carried out on the same machine tool as much as possible. (4) Arrange appropriate heat treatment process. The casting box has complex structure, uneven wall thickness, inconsistent cooling rate during casting, internal stress is easily generated, and the surface is hard. Therefore, after casting, sandblasting and tempering personnel should be arranged reasonably